A HIGH-RESOLUTION XPS STUDY OF A COMPLEX INSULATOR - THE CASE OF POROUS SILICON

High resolution XPS measurements of porous silicon samples with differ ent preparation histories are presented. Variation of photoelectron ta ke off angle and of flood gun conditions leads to the separation of em ission of near surface electrically insulated material from substrate silicon emission. Variation of the charging level produces differentia l shifting in the energies of emission of the porous silicon component , which shows a balance of elemental and oxidised silicon related to p reparation conditions. The systems studied display a sharp division be tween highly homogeneous well earthed elemental silicon and stable cha rged regions, and provide thus an example of the separation of spectra from a complex insulator-on-support system into individual components .